Method of enhanced oil recovery and intensification of production from oil, gas and condensate wells by means of hydromonitor radial overbalance formation penetration

ABSTRACT

The method includes installation in the well of high strength tubing, mechanical anchoring device, turning device, sealing device, deflector; running hydromonitor nozzle, wellbore trajectory control module, navigation system, work coil tubing section, flow re-distribution device, check valve and supply coil tubing section. By fluid supply into annulus between tubing and coil tubing and running coiled tubing, hydromonitor drilling of planned length of controlled radial channel in the formation is performed. Fluid with cuttings coming out the well through annulus between tubing and casing string, cleaned at surface and circulated back. After drilling, the work coil tubing section is retrieved from the formation and well circulation is performed until full carryover of cuttings. By mechanical turning device, the deflector is re-positioned to a different plane; the working cycle is repeated for the next radial channel. Milling of windows for all radial channels is performed beforehand during well preparation stage.

FIELD

This invention is related to oil and gas industry, and namely to methods for circulation of drilled wells with use of liquids and gases including change of well direction, and namely methods if enhanced oil recovery and intensification of production from oil, gas and condensate wells by means of hydromonitor radial overbalance formation penetration.

BACKGROUND

By the technique level there is a number of known drilling methods, for example, a method implemented with use of drilling device (patent RU 2118440C1, 27 Aug. 1998), including drilling of the main wellbore and its reinforcement with casing string with pipe fitted with a guiding element, running of drill string with motor, bit and oriented drilling of the first lateral, and in this process the guiding element deflects the tool. When required, in order to facilitate entry into one of deviated laterals, a re-entry device can be run into the deflecting device, and after that drilling of the second lateral is performed in similar way.

Deficiencies of the above-mentioned method include complexity of the device design, which leads to increase of financial costs for well construction, impossibility to include the main wellbore into operation, because the guiding element is not retrieved from the well, high radius of wellbore deviation, which results in the necessity of drilling an extended interval to the lateral entry into producing formation, necessity to reinforce the lateral with casing string and cement it.

The closest analogue of the declared invention is hydraulic drilling method (see US2012/0186875 26 Jul. 2012), which includes sealed installation of deflecting device with internal surface of work string on distal end of tubing work string, and the deflector is designed with an internal channel passing in it, and drilling string contains drill tubing with internal bore, close end and distal end, and a device of through flow having at least one channel providing for fluid communication between annulus generated by internal surface of tubing work string and internal bore of drill tubing when drilling tool is inserted into tubing work string, further the method includes connection of the drilling tool to the connecting string, entry of drilling tool into tubing work string, entry of at least part of drill tubing into the deflector, supply of drilling mud under pressure into annulus generated between tubing work string and connecting string, and drilling fluid under pressure passes in through flow device into drill pipe and comes out at distal end of drill tubing.

Deficiencies of the closest analogue include low efficiency of the method, caused by low coverage by radial channels in formation pay zone due to lack of navigation for drilling of channels and control over their trajectory, lack of opportunity to drill extended channels due to hazard of their uncontrolled passing beyond the formation boundaries and ingress into water-bearing intervals or their drilling in non-producing part of well profile.

SUMMARY

The invention objective is to remove the above-mentioned deficiencies by means of creation of a new method of enhanced oil recovery and intensification of production from oil, gas and condensate wells.

Technical deliverable of the declared invention is improvement of well productivity and oil recovery factor due to addition of drain area, coverage, removal of skin-factor and increase of formation matrix permeability, provision of an opportunity of target treatment of the formation due to directed impact on the deposit with controlled radial channels, opportunity to perform intensification without impact on casing string cement by significant pressure differential or chemical destruction; opportunity to perform intensification by significant pressure differential or chemical destruction; cleaning of the wellbore in the process of its drilling, which allows to efficiently use the technology both in carbonate and in terrigenous formations.

The above-mentioned objective of the invention is resolved by means of creating a method of enhanced oil recovery and intensification of production from oil, gas and condensate wells with use of hydromonitor radial formation penetration, including installation in the well of high strength tubing, deflector with internal channel passing in it, its linking and potential spatial orientation in the lower level of radial channel drilling, wellhead sealing, installation of downhole equipment of coiled tubing consisting of hydromonitor nozzle, wellbore trajectory control module, navigation system, work coil tubing section, flow re-distribution device, check valve, supply coil tubing section, fluid supply into annulus between tubing and coil tubing, passing of hydromonitor nozzle through sealing device, through the deflector to contact the rock, drilling of planned length of radial channel is performed with use of navigation system for control over current position of wellbore in the formation, and also with use of wellbore trajectory control module in order to assure radial channel drilling along the designed trajectory, after drilling through the formation the work coil tubing with the nozzle is retrieved from the formation and well circulation is performed until full carryover of cuttings, by means of activation of mechanical turning device, the deflector is re-positioned to a different plane, the working cycle is repeated for the next radial channel, milling of a separate window in casing string for each radial channel is performed before switch to implementation of the main operation for drilling of radial channels through the deflector, in the process of radial channel drilling wellbore trajectory is determined and changed by means of provision of work coil tubing with wellbore trajectory control module and navigation equipment.

For drilling of radial channels at next levels, supply and work coil tubing are retrieved from the well, tubing is unset from mechanical anchoring device, tubing landing joint installed in advance and equal to the length of transition to the next level is retrieved, tubing is set on mechanical anchoring device, work coil tubing section with navigation system, wellbore trajectory control module, hydromonitor nozzle is run into the well, after that works associated with drilling of radial channels are repeated.

In order to cut windows in casing string for radial channels, additional sand-jet device on coil tubing is run into the well, abrasive cutting of rectangular hole is performed with circulation, and then the equipment is pulled out.

Cutting of all required rectangular holes for drilling radial channels through casing string at one level using a fixed turn of the deflector by means of activation of mechanical turning device with discrete turning angle is performed during one trip of sand-jet device on coil tubing.

Fluid injection is performed into small annulus between tubing and coil tubing and/or small annulus between tubing and coil tubing and internal space of coil tubing.

BRIEF DESCRIPTION OF THE DRAWINGS

Brief explanation of the invitation essence is presented in graphical materials.

In FIG. 1 Scheme 1 of declared method.

In FIG. 2 Scheme 2 of declared method.

In FIG. 1-2:

-   1—check-valve; -   2—flow re-distribution device; -   3—mechanical anchoring device; -   4—turning device; -   5—sealing device; -   6—deflector; -   7—navigation system; -   8—wellbore trajectory control module; -   9—hydromonitor module; -   10—sand-jet cutting device; -   11—casing string; -   12—high-strength tubing; -   13—supply coil tubing section; -   14—work coil tubing section; -   15—full-circle milled area (“window”) in the casing string; -   16—passage hole (“window”) cut in casing string with sand-jet     cutting device.

DETAILED DESCRIPTION OF THE NON-LIMITING EMBODIMENTS

Further options are provided below, which are not exhaustive.

Deflector is run on high strength tubing into prepared for radial formation penetration well with milled “windows” in casing string in spots for drilling of radial channels and is installed with reference and when required with orientation in the interval of lower level of radial channel drilling. Downhole equipment on 38 mm coil tubing (flexible tubing) is run into the well (into 89 mm tubing). This equipment includes: hydromonitor nozzle, wellbore trajectory control module, navigation system, 32 (38) mm work coil tubing section of designed length equal to designed length of radial channels (up to 500 m and more), flow re-distribution device, check valve, supply coil tubing section. Then wellhead sealing is performed, and after that penetration fluid is supplied into annulus between 38 mm supply coil tubing section and 89 mm tubing, by means of supply coil tubing hydromonitor nozzle with work coil tubing section is passed through sealing device, comes out of the deflector to contact the rock/cement. Drilling of planned length of radial channel is performed with use of navigation system for control of current wellbore position in the formation, and also with use of wellbore trajectory control module to assure channel drilling along the designed trajectory. In this process fluid injection is performed into small annulus between tubing and coil tubing and/or small annulus between tubing/coil tubing and internal space of coil tubing. The pump is shut off and deflector is turned with guaranteed accuracy with use of mechanical turning device. Operation for drilling of the next channel is repeated. After drilling of required number of channels at one level, full pulling of coil tubing out of the hole is performed. Landing joint of designed length, which previously was installed in the top part of tubing string is retrieved for transition to the next level. Deflector is installed on tubing in the planned interval on mechanical anchoring device. The work cycle is repeated. After implementation of designed number of radial channels, full pulling of coil tubing and 89 mm tubing string out of the hole is performed.

Below is one more of potential examples with variation by scheme of method 2 (see example and FIG. 2 below) of the invention realization, which in no way limits all potential options of its realization. For convenience the example is provided with references to graphical materials.

[1] Assembly consisting of deflector (6) having a passing channel with side outlet, sealing device (5), turning device (4), mechanical anchoring device (3) is run on high strength tubing (12) into the killed well prepared for implementation of radial formation penetration.

The assembly can also include additional elements not limited by this list: linear stress compensator, disconnector, check valves and other.

By geophysical method the deflector is linked with its side channel to the interval of full-circle milled casing string (15). Tubing assembly is set on mechanical anchoring device (3) taking the link into account so that the deflector outlet (6) is aligned with open (full-circle milled) part of the casing string (15).

[2] There is another method (see FIG. 2) to assure communication of side outlet of the deflector (6) with formation by means of using sand-jet cutting of rectangular “window” (16) in the casing string (11). In order to perform this task, the above-mentioned assembly is run into not milled casing string, then it is set on mechanical anchoring device (3) with link by geophysical method.

[3] Further, sand-jet cutting device (10) on coil tubing (13) is run into the tubing (12), which comes to connection with the deflector and the end with the nozzle is directed to casing string wall (11). Fluid is injected into coil tubing (13) to create fluid circulation which comes out of the well in annulus between casing string (11) and tubing (12). Abrasive material (quartz sand, proppant, etc.) is added into the fluid flow on the surface, which passes through the device nozzle (10) and destructs casing string wall making a passage hole (16). Creation of a rectangular passage hole (16) is provided by moving sand-jet device nozzle down (10). Operation for drilling of radial channels is started after cutting of a hole in the casing string and pulling equipment for sand-jet cutting out of the hole.

In individual case, cutting of all required rectangular holes for drilling of radial channels at one level is performed during one trip of sand-jet device on coil tubing using fixed turn of the deflector due to activation of mechanical turning device with discrete turning angle.

[4] Assembly for radial formation penetration consisting of hydromonitor nozzle (9), wellbore trajectory control module (8), navigation system (7), work coil tubing section (14) is run into the well (FIG. 1) with tubing (12) on supply coil tubing section (13) with flow re-distribution device (2) and check-valve (1). The assembly for radial formation penetration can also contain additional elements not limited with this list of downhole equipment.

[5] Supply of wash fluid is performed into annulus between coil tubing (13) and tubing (12) in the process of coil tubing (14) and (13) running into tubing (12) in order to equalize pressure in the well. When depth of mechanical anchoring device (3) installation is achieved, increase of wash fluid injection flow rate to the design mode is performed, full circulation is achieved with fluid coming out in annulus between tubing (12) and casing string (11). Drilling of planned extension of radial channel is performed with use of navigation system (7) in order to control current position of the channel in the formation, and also with use of wellbore trajectory control module (8) in order to assure channel drilling along the design trajectory. Wash fluid coming out of the well is directed back into the well through the treatment system.

[6] Coil tubing (14) movement down is achieved by means of running coil tubing (13), this provides for hydromonitor nozzle (9) coming out of the deflector (6) and casing string (11), then hydromonitor drilling of radial channel of design length is performed in the producing formation.

[7] Determination of geographical coordinates of radial channel bottom in the formation and their reference to lithological profile is performed by means of navigation system (7) which transmits information to the surface by cable communication channel. Wellbore trajectory control model (8) controlled from the surface by hydraulic or cable communication channel is used to drill a radial channel along the design trajectory, change its trajectory when approaching boundary of the selected formation interval.

[8] When final design point (bottom) of radial channel is achieved, hydromonitor nozzle (9) on coil tubing (14) is retrieved from the formation with its installation below sealing device (5). Washing is performed to achieve full removal of cuttings from annulus between tubing (12) and casing string (11).

[9] After completion of circulation, coil tubing (14) is run with passing through turning device (4) required number of times (each coil tubing passing through turning device provides for deflector turn to a certain discrete angle) and thus deflector turn to the angle designed for drilling of the next channel is achieved.

[10] In cases when during well preparation for radial formation penetration full-circle milling of the casing string was performed or when during one trip of sand-jet device on coil tubing cutting of all required rectangular holes for drilling of radial channels at one level was performed, operation [6] is started, and then operations [7], [8], [9] are successively performed.

[11] In cases when during well preparation for radial formation penetration no full-circle milling of the casing string was performed, after retrieval of assembly on coil tubing (14) from the well, operation [3] is started, and then operations [4], [5], [6], [7], [8], [9] are successively performed.

[12] For transition to the next level of drilling of radial channels by profile, after implementation of drilling of all planned radial channels at one level, the assembly on coil tubing (13), (14) is pulled out of the hole. Tubing (12) is unset from mechanical anchoring device (3), tubing landing joint of design length (previously installed), providing for deflector lift to the next level is retrieved from the well.

[13] Tubing assembly is set on mechanical anchoring device (3) so that deflector (6) outlet is aligned with open (milled) part of the casing string (15).

[14] In cases when during well preparation for radial formation penetration no full-circle milling of the casing string was performed, deflector (6) outlet must be aligned with design interval of sand-jet cutting in the casing string (16). Works [3] are performed for cutting of such hole.

[15] Operations [4], [5], [6], [7], [8], [9] are successively performed for drilling of radial channels at each level of well profile.

[16] Operations [12], [13], [14] are performed for transition to each next level for drilling of further designed radial channels.

[17] Operations [4], [5], [6], [7], [8], [9] for drilling of radial channels at each level of well profile are successively repeated.

[18] After drilling of planned number of radial channels at all levels of well profile and well circulation to remove cuttings, tubing (12) is unset from mechanical anchoring device (3) and tubing (12) is completely pulled out of the hole.

[19] Then well completion is performed under individual plan of works.

Thus, application of the declared method provides for:

improvement of well productivity and oil recovery factor due to addition of drain area, coverage, removal of skin-factor and increase of formation matrix permeability;

opportunity of target impact on the formation due to directed drilling of controlled radial channels with big length;

opportunity to perform intensification without impact on casing string cement with significant pressure differential and chemical destruction;

opportunity to perform intensification by impact on the formation with significant pressure differential or chemical destruction;

cleaning of the wellbore during its drilling, which allows to efficiently use the technology, both in carbonate and in terrigenous formations. 

1. A method of enhanced oil recovery and intensification of production from oil, gas and condensate wells with use of hydromonitor radial overbalance formation penetration, the method comprising the steps of: (a) milling of a separate window in a casing string for each radial channel for drilling of a radial channel, (b) installing, in a well, a deflector having an internal channel passing through the deflector, wherein the deflector is configured to be spatially oriented in a lower level of radial channel drilling, a sealing device, a turning device, a mechanical anchoring device, and a high strength tubing, (c) wellhead sealing, (d) installing downhole equipment, the downhole equipment comprising: a hydromonitor nozzle, a wellbore trajectory control module, a navigation system, a work coil tubing section, a flow re-distribution device, a check valve, a supply coil tubing section, (e) supplying fluid into an annulus between the high strength tubing and the supply coil tubing section, (f) passing the hydromonitor nozzle through the sealing device and through the deflector to contact a rock, (g) hydromonitor drilling a planned length of the radial channel in a formation using the navigation system and the wellbore trajectory control module, wherein the navigation system is configured to control a position of a wellbore in the formation, wherein the wellbore trajectory control module is configured to ensure wellbore drilling along a designed route, (h) after drilling in step (g), retrieving the work coil tubing section with the hydromonitor nozzle from the formation, (i) circulating the fluid in the well until a full carryover of cuttings occurs, (j) re-positioning the deflector to a different plane via activation of the mechanical turning device, (k) obtaining and changing a wellbore trajectory during radial channel drilling using the navigation system and the wellbore trajectory control module, and (l) repeating a working cycle comprising steps (e) (k) for a further radial channel.
 2. The method of claim 1 further comprising drilling a further level of radial channels after step (l) comprising the steps of: (m) retrieving the supply coil tubing section and the work coil tubing section from the well, (n) unsetting the mechanical anchoring device with the high strength tubing, (o) retrieving a tubing landing joint, (p) setting the mechanical anchoring device with the high strength tubing, (q) running the work coil tubing section with the navigation system, the wellbore trajectory control module, and the hydromonitor nozzle into the well, and (r) performing steps (d)-(l).
 3. (canceled)
 4. (canceled)
 5. The method of claim 1, wherein step (e) comprises supplying fluid into the annulus between the high strength tubing and the supply coil tubing section and/or an internal space of the supply coil tubing section. 